Class: FastMcpPubsub::Service

Inherits:
Object
  • Object
show all
Extended by:
Delivery
Defined in:
lib/fast_mcp_pubsub/service.rb

Overview

Core PostgreSQL NOTIFY/LISTEN service for broadcasting MCP messages across Puma workers

Constant Summary collapse

MAX_PAYLOAD_SIZE =

PostgreSQL NOTIFY limit is 8000 bytes, leave some margin

7800

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.dedicated_connection ⇒ Object (readonly)

Returns the value of attribute dedicated_connection.



11
12
13
 
# File 'lib/fast_mcp_pubsub/service.rb', line 11

def dedicated_connection
  @dedicated_connection
end

.listener_thread ⇒ Object (readonly)

Returns the value of attribute listener_thread.



11
12
13
 
# File 'lib/fast_mcp_pubsub/service.rb', line 11

def listener_thread
  @listener_thread
end

.shutdown_requested ⇒ Object

Returns the value of attribute shutdown_requested.



12
13
14
 
# File 'lib/fast_mcp_pubsub/service.rb', line 12

def shutdown_requested
  @shutdown_requested
end

Class Method Details

.broadcast(message, client_id = nil) ⇒ Object

Publishes one MCP message to the cluster.

client_id names the SSE client the message answers; nil means it is for everyone, which is what a genuine notification is. A response carries an id because every worker receives every NOTIFY, and without one the worker holding an unrelated session would write this answer into it.



20
21
22
23
24
25
26
27
28
 
# File 'lib/fast_mcp_pubsub/service.rb', line 20

def broadcast(message, client_id = nil)
  envelope = envelope_for(message)
  envelope[:_pubsub_target] = client_id if client_id

  send_payload(envelope.to_json)
rescue StandardError => e
  FastMcpPubsub.logger.error "FastMcpPubsub: Error broadcasting message: #{e.message}"
  raise
end

.start_listener ⇒ Object 



30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
 
# File 'lib/fast_mcp_pubsub/service.rb', line 30

def start_listener
  unless FastMcpPubsub.config.enabled
    FastMcpPubsub.logger.info "FastMcpPubsub: Not starting listener - disabled in config for PID #{Process.pid}"
    return
  end

  if @listener_thread&.alive?
    FastMcpPubsub.logger.info "FastMcpPubsub: Listener already running for PID #{Process.pid}"
    return
  end

  FastMcpPubsub.logger.info "FastMcpPubsub: Starting listener thread for PID #{Process.pid}"

  @listener_thread = Thread.new do
    Thread.current.name = "fast-mcp-pubsub-listener"
    listen_loop
  end

  # Register shutdown hook
  at_exit { stop_listener }
end

.stop_listener ⇒ Object 



52
53
54
55
56
57
58
59
60
61
62
63
64
65
 
# File 'lib/fast_mcp_pubsub/service.rb', line 52

def stop_listener
  # A thread that has already died on its own still leaves its reference
  # behind, and every caller reads that reference as "a listener is
  # running". Clearing it is part of stopping, not a separate errand.
  return @listener_thread = nil unless @listener_thread&.alive?

  FastMcpPubsub.logger.info "FastMcpPubsub: Stopping listener thread for PID #{Process.pid}"
  @shutdown_requested = true

  wake_listener
  join_listener
  discard_dedicated_connection
  @shutdown_requested = false
end